Health risk assessment of heavy metals in exposed workers of municipal waste recycling facility in Iran.

Exposure to heavy metals (HMs) present in the particulate matter from municipal solid waste during pretreatment and recycling processes may pose a serious health risk to workers. This was the first study on the exposure of municipal solid waste (MSW) recycling workers to toxic metals. The concentrations of HMs (Cd, Pb, As, Co, Cr, Ni, Cu, Fe, Mn, and Zn) during personal exposure to PM2.5 among municipal waste recycling facility workers in Kashan City, Iran, were investigated from January 15 to March 15, 2023. The research was performed in the three main stages of the waste recycling process: dismantling, sorting, and collecting. PM2.5 samples were collected using a personal environmental monitor (PEM) attached to a sampling pump. The non-carcinogenic and carcinogenic health risk values and related uncertainty for waste recyclers from HMs inhalational exposure were calculated using USEPA methodology and Monte Carlo simulations. The results showed that the dismantlers exhibited the highest exposure concentrations of PM2.5 (mean 2148 ± 1257 µg m-3), followed by sorters (mean 1864 ± 965 µg m-3), and collectors (mean 1782 ± 876 µg m-3). Health risk assessment indicated that 95th percentile contents of Ni, As, Co, and Zn were responsible for the non-carcinogenic risk (HQ) values exceeding the acceptable level of 1. The contents of As, Ni, and Cr in PM2.5 caused a non-acceptable carcinogenic risk for waste recyclers due to inhalational exposure, as the carcinogenic risk (CR) values exceeded the acceptable threshold of 1 × 10-6. Monte Carlo simulation results revealed that the mean and median CR values from inhalational exposure to carcinogenic HMs exceeded the acceptable level of 1 × 10-6 for municipal waste recyclers. As results of this study indicated the high-risk to hazardous metals for waste recyclers due to occupational exposure in the MSW recycling sites, it is suggested to consider workers' exposure as the public health concern.

Critical air pollutant assessments and health effects attributed to PM2.5 during and after COVID-19 lockdowns in Iran: application of AirQ+ models.

Objectives: The aim of this study was to evaluate changes in air quality index (AQI) values before, during, and after lockdown, as well as to evaluate the number of hospitalizations due to respiratory and cardiovascular diseases attributed to atmospheric PM2.5 pollution in Semnan, Iran in the period from 2019 to 2021 during the COVID-19 pandemic. Methods: Daily air quality records were obtained from the global air quality index project and the US Environmental Protection Administration (EPA). In this research, the AirQ+ model was used to quantify health consequences attributed to particulate matter with an aerodynamic diameter of <2.5 µm (PM2.5). Results: The results of this study showed positive correlations between air pollution levels and reductions in pollutant levels during and after the lockdown. PM2.5 was the critical pollutant for most days of the year, as its AQI was the highest among the four investigated pollutants on most days. Mortality rates from chronic obstructive pulmonary disease (COPD) attributed to PM2.5 in 2019-2021 were 25.18% in 2019, 22.55% in 2020, and 22.12% in 2021. Mortality rates and hospital admissions due to cardiovascular and respiratory diseases decreased during the lockdown. The results showed a significant decrease in the percentage of days with unhealthy air quality in short-term lockdowns in Semnan, Iran with moderate air pollution. Natural mortality (due to all-natural causes) and other mortalities related to COPD, ischemic heart disease (IHD), lung cancer (LC), and stroke attributed to PM2.5 in 2019-2021 decreased. Conclusion: Our results support the general finding that anthropogenic activities cause significant health threats, which were paradoxically revealed during a global health crisis/challenge.

Long-term trends of Nitrogen oxides and surface ozone concentrations in Tehran city, 2002-2011.

BACKGROUND AND AIM: Tropospheric ozone is a problem with multi aspects - hazard to human health, plant, and welfare and a key factor to climate change, air pollution and atmosphere chemistry, as well. Behavior of ozone and nitrogen oxides (NO, and NO2) concentration is highly complex and variable; therefore, their trends as short and long-term were significantly attended. Most of the studies were carried out on the behavior of pollutant concentrations in North America, Europe, and East Asia, but few studies have been conducted in west Asia. The aim of this study was to assess daily changes and long-term trend of ozone and nitrogen oxides concentrations in Tehran city, Iran from March 2002 to September 2011. MATERIAL AND METHODS: Data were collected from 18 air quality monitoring stations. The data were sorted as daily mean of 10 years (daily changes) and annual mean for each year (long-term trend). One-sample test was used to assess the statistical significance. RESULTS: Current findings indicated that changes of ozone, NO, and NO2 concentrations are dependent from job shifts and photochemical reactions. Annual mean concentrations of ozone and NO2 were gradually increased, long-term trend of ozone and NO2 concentration indicated. The correlation between long term trend of ozone and NO2 was significant (p < 0.05). CONCLUSION: The controlling program was the most important factor in long-term concentration of ozone, and nitrogen oxides, but some problems and difficulties were accounted to perform controlling program.